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 * SPDX-License-Identifier: Apache-2.0
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 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

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 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
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/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.search.aggregations.bucket;

import org.opensearch.OpenSearchException;
import org.opensearch.action.index.IndexRequestBuilder;
import org.opensearch.action.search.SearchResponse;
import org.opensearch.common.xcontent.XContentBuilder;
import org.opensearch.index.query.BoolQueryBuilder;
import org.opensearch.index.query.QueryBuilder;
import org.opensearch.search.aggregations.InternalAggregation;
import org.opensearch.search.aggregations.bucket.filter.Filter;
import org.opensearch.search.aggregations.bucket.histogram.Histogram;
import org.opensearch.search.aggregations.metrics.Avg;
import org.opensearch.test.OpenSearchIntegTestCase;
import org.hamcrest.Matchers;

import java.util.ArrayList;
import java.util.List;

import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
import static org.opensearch.index.query.QueryBuilders.termQuery;
import static org.opensearch.search.aggregations.AggregationBuilders.avg;
import static org.opensearch.search.aggregations.AggregationBuilders.filter;
import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.core.IsNull.notNullValue;

@OpenSearchIntegTestCase.SuiteScopeTestCase
public class FilterIT extends OpenSearchIntegTestCase {

    static int numDocs, numTag1Docs;

    @Override
    public void setupSuiteScopeCluster() throws Exception {
        createIndex("idx");
        createIndex("idx2");
        numDocs = randomIntBetween(5, 20);
        numTag1Docs = randomIntBetween(1, numDocs - 1);
        List<IndexRequestBuilder> builders = new ArrayList<>();
        for (int i = 0; i < numTag1Docs; i++) {
            builders.add(
                client().prepareIndex("idx")
                    .setId("" + i)
                    .setSource(jsonBuilder().startObject().field("value", i + 1).field("tag", "tag1").endObject())
            );
        }
        for (int i = numTag1Docs; i < numDocs; i++) {
            XContentBuilder source = jsonBuilder().startObject()
                .field("value", i)
                .field("tag", "tag2")
                .field("name", "name" + i)
                .endObject();
            builders.add(client().prepareIndex("idx").setId("" + i).setSource(source));
            if (randomBoolean()) {
                // randomly index the document twice so that we have deleted docs that match the filter
                builders.add(client().prepareIndex("idx").setId("" + i).setSource(source));
            }
        }
        prepareCreate("empty_bucket_idx").setMapping("value", "type=integer").get();
        for (int i = 0; i < 2; i++) {
            builders.add(
                client().prepareIndex("empty_bucket_idx")
                    .setId("" + i)
                    .setSource(jsonBuilder().startObject().field("value", i * 2).endObject())
            );
        }
        indexRandom(true, builders);
        ensureSearchable();
    }

    public void testSimple() throws Exception {
        SearchResponse response = client().prepareSearch("idx").addAggregation(filter("tag1", termQuery("tag", "tag1"))).get();

        assertSearchResponse(response);

        Filter filter = response.getAggregations().get("tag1");
        assertThat(filter, notNullValue());
        assertThat(filter.getName(), equalTo("tag1"));
        assertThat(filter.getDocCount(), equalTo((long) numTag1Docs));
    }

    // See NullPointer issue when filters are empty:
    // https://github.com/elastic/elasticsearch/issues/8438
    public void testEmptyFilterDeclarations() throws Exception {
        QueryBuilder emptyFilter = new BoolQueryBuilder();
        SearchResponse response = client().prepareSearch("idx").addAggregation(filter("tag1", emptyFilter)).get();

        assertSearchResponse(response);

        Filter filter = response.getAggregations().get("tag1");
        assertThat(filter, notNullValue());
        assertThat(filter.getDocCount(), equalTo((long) numDocs));
    }

    public void testWithSubAggregation() throws Exception {
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(filter("tag1", termQuery("tag", "tag1")).subAggregation(avg("avg_value").field("value")))
            .get();

        assertSearchResponse(response);

        Filter filter = response.getAggregations().get("tag1");
        assertThat(filter, notNullValue());
        assertThat(filter.getName(), equalTo("tag1"));
        assertThat(filter.getDocCount(), equalTo((long) numTag1Docs));
        assertThat((long) ((InternalAggregation) filter).getProperty("_count"), equalTo((long) numTag1Docs));

        long sum = 0;
        for (int i = 0; i < numTag1Docs; ++i) {
            sum += i + 1;
        }
        assertThat(filter.getAggregations().asList().isEmpty(), is(false));
        Avg avgValue = filter.getAggregations().get("avg_value");
        assertThat(avgValue, notNullValue());
        assertThat(avgValue.getName(), equalTo("avg_value"));
        assertThat(avgValue.getValue(), equalTo((double) sum / numTag1Docs));
        assertThat((double) ((InternalAggregation) filter).getProperty("avg_value.value"), equalTo((double) sum / numTag1Docs));
    }

    public void testAsSubAggregation() {
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(histogram("histo").field("value").interval(2L).subAggregation(filter("filter", matchAllQuery())))
            .get();

        assertSearchResponse(response);

        Histogram histo = response.getAggregations().get("histo");
        assertThat(histo, notNullValue());
        assertThat(histo.getBuckets().size(), greaterThanOrEqualTo(1));

        for (Histogram.Bucket bucket : histo.getBuckets()) {
            Filter filter = bucket.getAggregations().get("filter");
            assertThat(filter, notNullValue());
            assertEquals(bucket.getDocCount(), filter.getDocCount());
        }
    }

    public void testWithContextBasedSubAggregation() throws Exception {
        try {
            client().prepareSearch("idx").addAggregation(filter("tag1", termQuery("tag", "tag1")).subAggregation(avg("avg_value"))).get();

            fail(
                "expected execution to fail - an attempt to have a context based numeric sub-aggregation, but there is not value source"
                    + "context which the sub-aggregation can inherit"
            );

        } catch (OpenSearchException e) {
            assertThat(e.getMessage(), is("all shards failed"));
        }
    }

    public void testEmptyAggregation() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("empty_bucket_idx")
            .setQuery(matchAllQuery())
            .addAggregation(histogram("histo").field("value").interval(1L).minDocCount(0).subAggregation(filter("filter", matchAllQuery())))
            .get();

        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(2L));
        Histogram histo = searchResponse.getAggregations().get("histo");
        assertThat(histo, Matchers.notNullValue());
        Histogram.Bucket bucket = histo.getBuckets().get(1);
        assertThat(bucket, Matchers.notNullValue());

        Filter filter = bucket.getAggregations().get("filter");
        assertThat(filter, Matchers.notNullValue());
        assertThat(filter.getName(), equalTo("filter"));
        assertThat(filter.getDocCount(), is(0L));
    }
}
